"Aage M.," as the interviewee was known in the media, was a well-known safe-cracker whose personal story shows him to be a relic of a parochial, cohesive, and largely nonviolent domestic underworld that has largely disappeared. To an extent Aage M. approached his safe-cracking career as law-abiding people generally approach their jobs. He used rational principles to maximize his income and reduce risk; however, he rejected the routine, monotony, and boredom of the typical work-a-day world of the general population. He thrives on challenge, excitement, and stimulation. He holds a positive self-image of himself as a skilled mechanic, "ethically" responsible in his conduct (notably in loyalty to cohorts), generous to his friends, solicitous of the welfare of his "girls," and nonviolent. He holds a counter-ideology that views everyone as exploitative of others. Society's institutions, particularly the criminal justice system, are viewed as hypocritical and unjust. He perceives these institutions as protective of the privileged, exploitative of the masses, and brutal with those who challenge the "system." Whereas, most people are programmed to comply with the system, he views himself as a challenger of the system and as an outsider whom the system seeks to crush. This article further discusses the value of criminological study based on observations of and interviews with criminals. 23 notes and 54 references